Slitherine

I am somewhat puzzled by this situation and need advice.

It is the 6th battle in a 7-battles generic campaign Pyrrhic vs. Roman. I got the decision fighting a significantly larger army or a Rearguard Action. I chose the Rearguard. I didn´t get to choose the units; rather, the game gave me a Closed Order Warband, 3 Mercenary Hoplites and a few Italian Foot.

All my troops are Above Average to Elite, but the Romans have over 3x the numbers. How to hold them for 24 turns I have no idea. There is a medium-sized wood on my left, and I could hide everything there, but I doubt this will be sufficient. Any thoughts?

I have often found there is something like a gap between the wood and the edge of the map which can be defended by the Warband with the light troops in the wood protecting its flank. I also find it helps to hide for as long as possible.
Occasionally you can go as fast as possible up the side of the map and hide and fight from a wood on the enemy side of the map.
It usually does not end well if you try and fight in the open.

I have only actually won (40%/25%) once. For all others battles it is a case of avoiding loosing too much by the last move.

Yeah I think the Romans will slice me up. The game system really favours the stronger side, good for the AI, but playing for time with a much weaker army is perhaps a bit more difficult than irl.

Remember, you only have to avoid loosing. Also the heavy enemy troops do not get on well in woods so your medium troops can hold them off.
Slingers, archers and javelin throwers can be a bit of a nuisance though.
You can always loose that battle then go back and try again to see if you get a better map - you will always be outnumbered though.